Brown algae, belong to the Laminariaceae family and are found in abundance in central and southern Japan and Korea. Though mostly used as sources for alginic acid, these algae are also widely consumed as food in many Asian and several European countries. Brown algae have two major chemical groups: polysaccharides and polyphenols. Polysaccharide components include alginates, laminarin and fucoidans. Brown algal polyphenols are specifically called phlorotannins. Among categories of phlorotannins, eckol derivatives are pharmacologically prominent. These polyphenolic compounds are characterized by a dibenzo-1,4-dioxin unit in the molecular skeleton which is found only in some specific brown algae such as Eisenia and Ecklonia species.
Medicinally active brown algae extracts are typically alcohol extracts of the dehydrated leaves of the brown seaweed of the Laminariaceae family. An example is a purified Ecklonia cava extract standardized to contain approximately 92% phlorotannins and known by the brand name SEAPOLYNOL (also known as PH100). This formulation of Ecklonia cava extract has been approved as a New Dietary Ingredient (NDI) for use by adults and children over the age of 12 and is currently being consumed by humans in dietary supplements marketed in the US, Korea, China and Japan.
A variety of physical or physicochemical characteristics of the active substance are relevant for the preparation of solid oral dosage forms, (e.g., oral powders, granules, pellets, tablets, capsules, chewable tablets, dispersible tables, troches or lozenges), such as, for example, correct assay, content and mass uniformity, chemical and physical stability of the drug product, proper dissolution rate, physical characteristics of the drug substance such as, for example, bulk densities (i.e., poured and tapped density) Hausner Factor, particle morphology, shape, the ratio of length to width for needles, size distribution, electrostatic charging and surface adhesive properties.
Brown algae extracts have a variety of challenging physiochemical properties relevant for preparation of a solid oral dosage form. Depending on the method of preparation, formulations of the extract can be highly hygroscopic, poorly disintegrated or with poor flow properties which leads to tablets with insufficient hardness, poor coating, poor disintegration properties or poor productivity. Accordingly what is needed are solid dosage forms which satisfactorily addresses the above problems.